In exhaust systems of automobiles, the coupling or joint between the engine exhaust manifold and the catalytic converter is subjected to extreme physical conditions of temperature, vibration and flexure and twisting due to relative movement of the manifold and the catalytic converter inlet pipe. Additionally, the joint must meet stringent requirements in respect to sealing against exhaust gas leakage. Such a joint must also be of low cost and lightweight and have a long operating life to meet the needs of the automobile industry.
The foregoing requirements and the problems attendant thereto were specifically addressed in the making of the subject invention; however, it will be appreciated that the invention is useful in other applications even though not subject to the aforesaid requirements. For example, the invention could be used in other automotive applications such as the air supply pipe to the exhaust system and in nonautomotive applications such as piping systems for various fluids.
In the prior art, the Hall U.S. Pat. No. 4,209,177 discloses a flexible joint adapted especially for use in the exhaust system of an automobile. The joint of this patent utilizes a cast metal manifold with a flared end which receives a high temperature spherical seal on the end of the exhaust pipe, the seal being seated against an annular stop flange on the pipe. A clamping flange behind the stop flange is secured to a clamping flange on the flared end of the manifold by a pair of spring loaded bolts.
The Carr et al U.S. Pat. No. 3,995,889 discloses a pipe line ball joint for releasably connecting adjacent ends of two conduits. A ball member on one conduit is received by a socket member on the end of the other conduit and a ring mounted on the ball member is locked to the socket member by cooperating hooks and lugs which are engaged by relative rotation and held in place by lock pins.
The Laurent U.S. Pat. No. 2,158,131 discloses a swivel pipe coupling of the ball and socket type. In this its rear end which seats against a thrust ring bearing against a packing ring. The locking ring fits over the end of the socket member on the other pipe and has inwardly directed lugs with inclined faces adapted to cooperate with lugs on the socket member so that rotation of the locking ring forces the thrust ring against the packing ring toward the interior of the socket. The locking ring is held in its locked position by a bolt extending between the socket and the locking ring in a lateral direction. A coil spring is disclosed between the pair of packing rings to force the packing rings apart by a compressive force on the packing rings.
It is also known in the prior art to use an undulant spring in a connector for electrical conduits. In this connector, a receptacle shell and a plug shell are coupled together by a coupling ring having a locking ring inside thereof and disposed over the inner end of the plug shell. A first pair of bayonet pins extend through the coupling ring and through slots in the locking ring and into slots on the plug shell to hold these members together with a wave spring between the plug shell and the coupling ring. A second pair of bayonet pins are provided on the inner end of the receptacle shell which are in alignment with a pair of cam slots on the locking ring. When the plug shell is moved toward the receptacle shell, the second pair of bayonet pins engage the cam slots which causes rotation of the locking ring. This rotates the locking ring to a position where it is clear of the first pair of bayonet pins and the coupling ring is released thereby so that the spring pushes it toward the receptacle shell. This causes the first pair of bayonet pins to exert a force on the locking ring and rotate it relative to the plug shell. This rotation brings the second pair of bayonet pins into a locking relation with the cam slots so that the plug shell cannot be withdrawn from the receptacle shell.
A general objective of this invention is to provide an improved flexible joint for pipes which overcomes certain disadvantages of the prior art.